1. Field of the Invention
The present invention relates to a semiconductor electronic device typified by MOSFET or the like, and particularly to a structure suitable for use in a semiconductor electronic device using an SOI substrate and a method of manufacturing it.
2. Description of the Related Art
According to a reference: xe2x80x9cSIMOX-LSI Technology Latest Reportxe2x80x9d by High-Technology Promotion Institute Corp., p 220, issued in 1998 (in the tenth year of Heisei), attention has been focused on an electronic device formed over an SOI (Silicon On Insulator) substrate as a device having excellent characteristics such as low power consumption, speeding-up, etc. Various element technologies about the design, production, etc. of the electronic device have been studied together with a wafer manufacturing technology. As shown in the reference, a process for forming silicides has been widely used to reduce sheet resistances of source and drain regions and a gate electrode region of a transistor.
However, the silicides have features that they are selectively formed by reaction with a metal and Si alone and they will not be formed without reaction with the metal and SiO2. Since a micro device is short in gate length, silicides are grown so as to seat below or get under side walls formed over side walls of a gate electrode upon formation of the silicides in its source and drain regions, and they reach near a gate oxide film. Thus, this will create problems such as an increase in gate leakage current, a reduction in gate withstand voltage, a short channel effect, etc.
In order to solve the above-described problems, an object of the present invention is to provide a structure suitable for use in a semiconductor electronic device, wherein each of side walls provided over sides of a gate electrode of a field effect transistor formed over a substrate has a structure convex toward the substrate side, and silicides are formed over a source and drain of the field effect transistor and a gate electrode thereof and not grown to the portion under the side walls of the gate electrode.
Further, the present invention provides a structure suitable for use in a semiconductor electronic device, wherein side walls composed of silicides, which are lower than side walls formed on the sides of a gate electrode of a field effect transistor formed over a substrate, are formed in contact with the side walls formed on the sides thereof, and silicides are respectively formed over a source, a drain and the gate electrode of the field effect transistor and not grown to the portion under the side walls of the gate electrode.
Furthermore, the present invention provides a method of manufacturing a semiconductor electronic device, which is capable of easily forming the above structure in a simple process.
Typical ones of various inventions of the present application have been shown in brief. However, the various inventions of the present application and specific configurations of these inventions will be understood from the following description.